Research And Design Of Piezoelectric Ceramic Driving Power Based On Multiple Half-bridge Parallel Topology

Piezoelectric ceramics have the advantages of high displacement resolution,fast response,wide frequency band and no electromagnetic interference.The shaking table made of piezoelectric ceramics can be used to simulate all kinds of vibration environments that related products may encounter in transportation,installation and use.It is widely used in material structure test,aircraft dynamic simulation,automobile test and building seismic simulation and other fields.The output performance of the piezoelectric ceramic shaking table depends on the piezoelectric ceramic driving power supply,while the domestic high-power piezoelectric ceramic driving power supply mainly depends on imports.With the update and iteration of the test load,the output power of the piezoelectric ceramic driving power supply has been unable to meet the testing requirements of the piezoelectric ceramic shaking table.In this thesis,the multi-channel half-bridge parallel circuit topology is used as the main power loop,and a set of high-voltage,high-current and wide-band piezoelectric ceramic driving power supply including software and hardware is designed.The key problems involved,such as the output performance of the drive power supply,the performance of the control circuit and the characteristics of electromagnetic compatibility,are deeply analyzed,and the detailed solutions are given.The main research contents include the following aspects:1.The structure and working principle of the piezoelectric ceramic shaking table system are analyzed.According to the design requirements,the traditional half bridge driving circuit is improved.In view of the weak output current capacity of the single half bridge,this thesis uses the multi-way half bridge parallel circuit for output current superposition output,and determines the overall design of the piezoelectric ceramic driving power supply.2.The topology of the multi-channel half-bridge parallel circuit is analyzed deeply,the working state of the six-way half-bridge parallel circuit is analyzed,and the output current and voltage ripple in each state are derived,and the expressions of current and voltage ripple are extended to N-way parallel.The arm crosstalk of the half-bridge circuit is theoretically studied and analyzed,and a simulation model is built to verify the influence of parasitic parameters on crosstalk.3.The hardware circuit of piezoelectric ceramic driving power supply is designed.Through the analysis of the system design index,the selection and schematic design of controller,analog-to-digital converter,MOSFET driver chip and communication chip are completed.Aiming at the problem of electromagnetic interference in switching power supply,an EMI filter is designed.4.The software system of piezoelectric ceramic driving power supply is designed,including the ADC driver,random position PWM wave generation,closed-loop control algorithm and communication program.In order to solve the problem that the traditional fixed switching frequency has large harmonics in the integral multiple frequency of switching frequency,the random position PWM wave modulation mode is adopted to distribute the harmonics of the integral multiple frequency of switching frequency evenly to each frequency band.5.According to the software and hardware structure designed in this paper,the prototype of piezoelectric ceramic driving power supply is built,and the experimental test is carried out.Under the piezoelectric ceramic load of 6.5μF,the output voltage is 0V ～ 1080 V,the peak output current is 33 A,and the output signal frequency is adjustable from 5Hz to 2kHz.The sine wave output test,random signal output test,output stability test and conducted interference test are carried out.The test results show that the driving power supply meets the requirements of the piezoelectric ceramic shaking table.